[AMRadio] Loading antenna with BC 610 E

Warren Elly w1gud at tampabay.rr.com
Thu Jan 17 20:13:04 EST 2008

What my BC-610I has is an so239 mounted in the sidepanel just below  
the feed thrus.
its connected to the feedthrus...
i have a dowkey antenna relay hung off of it, and feed 375 watts out  
all day long into 50 ohms. I also pretune into a dummy load the same  
I use a tuner rated at 3k watts to tune 470 ohm feeders on a full wave  
loop on 75. using a 5kv 4 to 1 ballun to
bring the coax into the shack.
73 warren w1gud

On Jan 17, 2008, at 12:48 PM, ne1s at neandertech.com wrote:

> ----- Original Message -----
> Subject: [AMRadio] Loading antenna with BC 610 E
> Date: Thu, January 17, 2008 11:32
> From: "John King" <k5pgw at yahoo.com>
>> I would appreciate recommendations regarding a
>> "loading" device to help transfer RF from the tank
>> coil to the antenna. Will installing a C2 from output
>> to ground tune the reactance out of the feed line and
>> facilitate loading the dummy load better or loading
>> the Coax feedline to the antenna??
> Hi John,
> I believe what you want to do is put a variable capacitance in  
> series with
> the output link to resonate it. This should be connected such that the
> rotor of the capacitor is grounded/connected to the coax braid, and  
> the
> stator connects to one end of the link. The coax center conductor gets
> connected to the opposite end of the link. About 1200pF maximum  
> should be
> adequate for all bands except 160M. If you operate 160M you can put a
> large 1000pF transmitting mica in parallel with the variable capacitor
> when you operate there.
> I don't have experience with an actual BC-610, but know folks that  
> do, and
> use the above method (W1CKI, for one). Also, I have a homebrew rig  
> that
> operates up to 300W output and uses BC-610 coils with the above  
> method. I
> use the three-section ganged air variable from a late 1920s-era TRF
> broadcast radio. The spacing between rotor & stator seems adequate for
> this power level with this vintage capacitor. More modern broadcast  
> air
> variables may not be. All three stators, ~400pF each, are connected in
> parallel.
> GL,
> -Larry/NE1S
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